In recent years, there is used a cluster technology as a technology for improving availability in a hardware failure or an application failure. In a storage system including plural storage apparatuses, there is known a technology of improving availability of the system when a failure occurs in a first storage apparatus, by feeding data which is to be fed to the first storage apparatus, to a second storage apparatus by a host computer (PTL 1).
PTL 2 manages a situation of a virtual logical volume (hereinafter, referred to as VVOL) configured by plural virtual areas and detects a VVOL under an inappropriate situation. The VVOL is related to a pool for providing a storage area. PTL 2 tries to improve a situation by migrating the VVOL under the inappropriate situation from a current pool to other pool.